Light-emitting diode (LED) has low power consumption, long operation lifetime, shack-proof, compact size, fast reacting rate and stable light-emitting wavelength and so on, and therefore LED is suitable for various lighting purposes. As shown in FIG. 1, the conventional method of manufacturing the LED chip comprises forming a light-emitting stack (not shown) on a substrate 101, and forming cutting trenches 103v, 103h to separate the light-emitting stack and produce a plurality of LED chips 102. However, because most of the conventional LED chips are produced by laser-cutting which might produce byproducts when cutting the light-emitting stack due to the limitation of the laser beam size, the byproducts could cause current leakage easily. As a result, a width D of the cutting trenches 103v, 103h must maintain at least 20 μm to avoid the above mentioned situations. Nevertheless, if the areas of the cutting trenches can be optimized, the utilized area of the light-emitting stack can be increased by 25%.